Method and apparatus for tensioning material



Juq 26, 19 34. v c, 1,964,241

METHOD AND APPARATUS FOR TENSIONING MATERIAL Filed June 11, 1931 '3 Sheets-Sheet 1 INVENTOR Mam June 26, 1934. c. E. BEDELL METHOD AND APPARATUS FOR TENSIONING MATERIAL Filed June 11, 1931 3 Sheets-Sheet 2 INVENTOR Patented June 28,

Carl E. ltiedell, Sherrard, W. Va, assignmto Mesta Machine Company, Pittsburgh, Pa, a

corporation oi Pennsylvania.

Application dune Ill, 1931, Serial No. 543,623

ATENT OFFICE 16 Claims.

The present invention relates broadly to the art of metal working, and more particularly to an improved method and apparatus by means of which metal while being worked may be maintained under a substantially constant tension condition.

In the art of continuous rolling of strip or sheet material, the tension maintained on the material during the rolling operation is in many cases an extremely important factor. It not infrequently happens that tension is utilized as a means for at least in part obtaining the desired flatness, or for maintaining the material in line in the roll passes. Under present conditions of operation, evenwith automatic controls for the rolls by means of which the metal is acted upon, it frequently happens that there is a very appreciable change in tension from time to time. in many cases the change is an almostinstang taneous one, while in other cases there may be a gradual fluctuation in one direction or the other. With many processes it has been found that a tension variation in addition to afiecting the fiatness and the accurate travel of the material, also affects the gauge to a very appreciable extent.

' The present invention has for one of its objects the provision of a tension mechanism adapted to operate directly on the material intermediate adjacent treatment zones and effective for 3 maintaining a uniform tension condition in the material between such zones. The expression treatment zones as used herein is intended to constitute a generic designation of rolls, reels, coilers, and the like located usually at somewhat as spaced points and successively operable on a given portion of the material, the material being simultaneously subjected to operation in the difierent zones.

In the accompanying drawings 1 have shown more or less diagrammatically and by way of illustration only, a preferred embodiment of the present invention. In the drawings:

Figure l is a side elevational view 01 one form of apparatus constructed in accordance with the present invention and efiective for maintaining tension uniformity;

figure 2 is a view partly in detail section oi a portion of the structure illustrated in Figure 1;

ure 3 is an elevational view looking at the apparatus of Figure 2 from the right hand end thereci;

Figure 4 is a transverse sectional view on the line IV-IV of Figure 2, looking in the direction oi the arrows; and

Figure 5 is a sectional view of the structure on the line VV of Figure 1.

Referring more particularly to Figure 1 of the drawings, there are illustrated adjacent treatment zones A and B, which zones are herein shown as comprising mills of the four-high type between the working rolls 2 of which is adapted to pass the material M being treated. The showing of Figure 1 is predicated on the assumption that it is desired to maintain on the material intermediate the treatment zones A and B a substantially constant total tension regardless of any lack of synchronism or proper adjustment as between the speed of operation of the metal working means in the respective zones. In full lines the material is shown in the path through which it normally travels when the two mills shown in Figure 1 are running under properly correlated speed conditions, while in chain lines I have shown the position of the material caused either by an increase in the speed of operation of the right hand mill or a decrease in the speed of operation of the left hand mill. In the absence of special means. slack in the material such as represented by its chain line position would be efiective for completely destroying any tension condition. y

In accordance with the present invention, I provide a tensioning roller 3 effective directly on the, material intermediate the zones A and B and adapted to move from its normal full line position into a position such as indicated in chain lines when and if the working conditions become so unbalanced in the respective treating zones as to provide slack therebetween. The tension roller 3 is carried by a tension slide 4 caused to move in a truly perpendicular direction by means of guides 5 herein illustrated as comprising a'series of suitably disposed rollers efiective on opposite sides of the tension slide. Pivotally connected to the lower end of the tension slide is a pltman 6 95 extending into a housing 7 between guide rollers 8 mounted to prevent lateral movement of the pitman in a direction perpendicular to the plane of the drawing of Figure 1 while permitting angular movement in the plane of the paper.

in Figure 2 the pitman 6 is shown as being in its extreme lower position, this being the position corresponding to that which it will occupy with the tension roller 3 in its full line position of 105 Figure l. The pitman is provided with a rack 9 on one face thereof adapted to mesh with teeth 10 of a. gear 11 having an axis of rotation 12 eecentrlcally disposed with respect to the periphery of the gear. Secured to the ar and likewise 3m movable about the shaft 12 constituting the axis of rotation is an arm 14 projecting upwardly from the housing 7 through a slot 15 therein. The arm 14 is herein illustrated as being of T shaped cross section and as provided with a series of graduations 16 adapted to be used as a scale in the adjustment of a counterweight 17 along the arm.

Extending through the gear 11 is a pin 18 which is concentrically disposed with respect to the periphery of the gear and on the ends of which are mounted plates 19 which carry therebetween spaced rollers 20 forming a roller support for the pitman 6 and preventing the same from moving outwardly away from the teeth 10.

By reason of the construction just described, it will be apparent that under conditions of operation of the adjacent mills such as would tend to produce slack in the material as indicated in chain lines in Figure 1, the counterweight 17 will be effective for swinging the arm 14 in a clockwise direction from its full line position of Figure 1 into its chain line position. This movement will be effective for swinging the pin 18 in an are about the shaft 12 thereby drawing the plates 19 to the right and maintaining the teeth of the rack 9 in engagement with the teeth of the gear 11. This movement will also be effective for raising the pitman 6 and thereby elevating the tension roller 3.

It is to be noted that with the parts in the full line position of Figure 2 the radius effective as a lever arm in lifting the pitman 6 is designated by the reference letter R. As the arm 14 swings in a clockwise direction this radius becomes gradually less and less until a minimum radius is effective. As the radius decreases in length, the effectiveness of the counterweight 1'7 increases inasmuch as the ratio of the radius R to the distance D along the arm 14 varies. The arrow P represents the direction of pressure application on the material through the medium of the tension roller 3. As the tension roller 3 moves upwardly, the length L remains substantially constant, the angle a becoming greater and greater. During the same time, the angle a likewise becomes greater and greater.

The effective tension is indicated by the arrow T, this tension being the pull exerted on the material either directly by the action of the adjacent mills, which control the maximum tension, or that exerted by the counterweight 17 through the medium of the tension roller 3, this representing the minimum tension. By proper adjustment of the mills it is possible to insure a condition of operation in which the tension is always within the limits controlled by the tension roller.

The adjustment of the parts is such that T sin a=P, T representing the tension and P the effective pressure exerted by the tension roller as indicated in Figure 1. The apparatus is also designed that I it being understood that W in this equation equals the effectiveness of the counterweight 17. In the first equation the only variable is sin a, while in the second equation there are two variables, these being sin a and R.

It will thus be seen that as the mills themselves become less and less effective for exerting the desired tension, the counterweight 17 becomes more and more effective whereby a substantially constant condition P is always maintained. If the scale 16 is originally calibrated in terms of pounds of tension or total tension, it is possible by a simple adjustment of the counterweight along the arm 14 ,to set the parts in such manner as to maintain any desired constant tension at all times. Briefly, therefore, the apparatus in question may be considered as means automatically compensating for the variation in tension exerted on the material between adjacent working zones by the respective apparatus in those zones.

In order to insure the desired full line position of the tension roller 3, as illustrated in Figure 1, there is preferably provided an adjustable mounting 21.

The advantages of the present invention arise from the provision of a method and apparatus whereby the desired constancy of tension may be maintained on moving material during its simultaneous treatment in a plurality of treatment zones regardless of the proper continued co-ordinated operation of the equipment provided in such zones.

While I have herein illustrated and described a preferred embodiment of the present invention, it will be understood that changes in the construction and operation of the parts may be made without departing either from the spirit of the present invention or the scope of my broader claims.

I claim:

1. The combination with a pair of metal working devices in spaced relationship and adapted to be simultaneously operative on a given piece of material, of means intermediate said devices and effective on the material therebetween for maintaining a substantially constant tension thereon, said means including a counterwei ht so constructed and arranged that its effectiveness increases as the slack in the material increases.

2. The combination with a pair of metal working devices in spaced relationship and adapted to be simultaneously operative on a given piece of material, of means intermediate said devices and effective on the material therebetween for maintaining a substantially constant tension thereon, said means including a counterweight and a linkage system through which the counterweight is effective, said counterweight and linkage system being so constructed and arranged that in operation a radius of said system gradually decreases in its efiective length as the length of the material between the devices tends to increase.

3. The combination with a pair of metal working devices in spaced relationship and adapted to be simultaneously operative on a given piece of material, of means intermediate said devices and effective on the material therebetween for maintaining a substantially constant tension thereon, said means including a pressure roller eflective against the material, and means constructed and arranged to displace the roller as the length of the material between the devices increases.

4.. The combination with a. pair of metal working devices in spaced relationship and adapted to be simultaneously operative on a given piece of material, of means intermediate said devices and effective on the material therebetween for maintaining a substantially constant tension thereon, said means including a pressure roller effective against the material, means for displacing the roller as the length of the material between the devices increases, and a linkage system connecting said last mentioned means to the roller, the said linkage system being so constructed and arranged that its effectiveness increases as the displacement of the roller increases.

5. A tension device including a tension slide,

a counterweight for efiecting movement of said slide, and a linkage system intermediate the counterweight and slide constructed and arranged to increase the eflectiveness of the counterweight as the slide is displaced from a given position.

6. In a tension device, a tension slide including a rack bar, a gear having an eccentric mounting and meshing with said rack bar, a counterweight for rotating said gear, and means for maintaining the rack bar and gear in engagement as the gear rotates about its eccentric axis.

7. A tension device including a movable tensioning member, a weight having an eccentric mounting for moving said member, and means for maintaining operative engagement between said member and the weight upon movement of the weight about said mounting.

8. In a tension device, a slide including a'rack, a gear having an eccentric mounting and meshing with said rack, a frame connected to said gear and embracing said slide for maintaining the rack and gear in operative relationship, and means for effecting a rotative movement of said gear about its eccentric mounting.

9. In a tension producing device, a member effective for'producing a pressure P on the material in which tension is to be maintained, a weight W effective through an angle a for effecting movement of said member, said weight being so constructed and arranged as to operate on said member through a gradually changing radius R in which the relationship of the parts is such that ing the material and effective through an angle a to exert a tension T on the material by main taining the relationship T sin a=P.

12. In the method of tensioning material be-= tween two working zones to maintain a substan tially constant tension between said zones as the length of the material therebetween increases, which comprises displacing the material intermediate said zones, and increasing the effectiveness of the displacing means as the amount of displacement increases.

13. In the method of working material, the steps comprising subjecting the material at spaced points to a working treatment, and pressing the material and varying the pressure inversely with a variation in the tension on the strip material.

14. In the method of working material, the steps comprising subjecting the material at spaced points to a working treatment, and pressing thematerial intermediate such points and at a fixed distance from one of said spaced points and varying the pressure inversely with a variation in the tension on the strip material.

15. A tension device comprising a tension ap- 130 plying member, an operating member connected with said tension applying member, a counterweight for effecting movement of said operating member, and connections between said operating member and said counterweight constructed and 195 arranged to increase the effectiveness of the counterweight as the operating member is displaced from a given position.

16. The combination with a pair of metal working devices in spaced relationship and adapted to be simultaneouslyv operative on a given piece of material, of tensioning means intermediate said'devices and effective on the material therebetween, and means for moving said tensioning means against the material, said means 115 being so constructed and arranged as to apply to the material as the latter tends to become slack a pressure which increases in approximate proportion to the distance moved by the tensioning means.

CARL E. BEDELL. 

